Glucosamine, which occurs naturally in the body, plays a key role in the construction of cartilage, or the tough connective tissue that cushions the joints. Glucosamine stimulates the production of glycosaminoglycans (the key structural components of cartilage) as well as the incorporation of sulfur into cartilage. Sulfur is necessary for making and repairing cartilage.
Clinical studies report that glucosamine may be effective in treating and possibly slowing the progression of osteoarthritis. This is a type of arthritis caused by continuous wear and tear on the joints leading to inflammation, breakdown, and eventual loss of cartilage. The tissues most affected by osteoarthritis are the weight bearing joints, such as the knees and hips, as well as the joints in the hands.
Studies suggest that glucosamine may be at least as effective as some of the medications frequently used to treat this joint condition, but with fewer gastrointestinal side effects. The medications used to treat osteoarthritis are known as nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and piroxicam. NSAIDs may cause stomach upset, cramps, constipation, diarrhea, and in some cases, stomach ulcers.
Glucosamine is often taken with chondroitin, another supplement thought to be effective in treating arthritis. These substances are often combined with manganese as well, a trace metal that is also needed for building cartilage.